The present invention relates generally to packet based data communication networks, and more particularly to proxy agent control of asynchronous transfer mode (ATM) networks.
Today, telecommunications continues to shift from an emphasis on circuit switched networks, such as the Public Switched Telephone Network (PSTN) to faster, more flexible packet-based data networks. Internet protocol (IP) and ATM protocol technologies provide the processing bandwidth and speed necessary to communicate real time voice, data, and graphics between end users.
In a typical ATM network supporting voice communication, the ATM network is utilized for interconnecting trunking gateways linked to traditional circuit switched based PSTN networks and/or access gateways linked to telephone users access devices such as analog phones, PBXs, etc. For example, an end user may have a phone set connected to ATM access gateway. The ATM gateway interfaces with the user's phone set and translates the voice into data packets. The gateway then sends the packets to an ATM switch (or a network of ATM switches) for routing. On the other side of the ATM switch, a second access gateway interfaces with the receiving end user and translates the packetized data into a real time voice call for the user.
ATM switches route ATM data packets over virtual circuits. When Switched Virtual Circuits (SVC) are utilized by the ATM network the virtual circuits are established on demand in real time. Thus, for each call, a virtual circuit from the originating end user to a destination end user must be setup by the ATM switch(s). The intelligence for controlling the establishment of these virtual circuits can be included within the ATM switch or within a "proxy agent." A proxy agent is typically a separate network element connected to both the gateways and the ATM switch to provide the third party signaling necessary to setup and maintain a call connection. Proxy agents communicate with ATM switches and gateways by "proxy signals," which are received on one or more ports of an ATM switch. Each ATM switch port controls a set of communication circuits within the switch interior to establish virtual circuits to a called party. For example, an ATM switch may include four ports, each of which controls hundreds of communication circuits within the switch. ATM switches typically include a timer for taking down all virtual circuits when a proxy signal control fails. For example, the ATM Forum's UNI proxy signaling standard defines this timer as a configurable timer. (In this application, this timer is designated as T.) Thus, failure of proxy signaling between the proxy agent and an ATM switch port results in termination of many call connections. This, of course, results in reliability problems, a key concern for any network operator. Typically in case of proxy agent failure, control can be redelegated to another port and/or another proxy agent. However, the switch must be manually reconfigured to match the new port to the corresponding circuit connections. This, of course, takes time and reduces network availability.
Therefore, it is desirable to have methods and systems to overcome the disadvantages of proxy agent signaling in data networks, particularly ATM switch-based networks.